This invention relates generally to the art of finishing and cleaning molded articles by directing particulate material against the rough molded article. Impeller systems for directing metal shot against cast metal articles for cleaning the articles is well known. It is also known to de-fin rough cast metal parts, such as engine blocks, by blasting parts with large metal particles. U.S. patent application Ser. No. 382,833 filed May 27, 1982 assigned to the assignee of this application, shows such a de-finning system.
The present invention relates more specifically to the finish cleaning of molded sand cores which are made by molding a mixture of sand and a binder, to form a core that may be of complex shape having holes, projections, notches, and other irregularly shaped areas. Such articles are far more delicate than the articles which have heretofore been finished by blasting with an impact media, often metal particles moving at high velocities. Accordingly, prior art blasting apparatus and methods have not been adaptable to the problem of automated cleaning of molded sand cores, and the present rubbing by hand methods for cleaning cores are unacceptable because they are time consuming and expensive.
It is an object of the present invention, therefore, to provide an improved method and apparatus for removing flash and other excess material from sand cores by directing a fluidized media of impact particles against the sand cores.